Fine mapping of quantitative trait Loci on bovine chromosome 6 affecting calving difficulty.
Calving difficulty is an economically and ethically important trait for dairy cattle breeding. The aim of the present paper was to refine the position of a previously detected quantitative trait locus (QTL) affecting calving difficulty (direct effect) in Norwegian Red dairy cows. A granddaughter design consisting of 18 elite sire families and a total of 713 sons was genotyped for 154 markers spanning the QTL region, and the trait data were analyzed by using a combined linkage and linkage disequilibrium approach. A highly significant QTL was detected in a 150-kb interval between the markers LAP3_281 and BTA-114677. Additionally, there were some indications of a second QTL between the markers BTA-75776 and BTA-75780 located less than 500 kb apart. Several candidate genes may be identified close to these QTL. Of these, a cluster of genes expected to affect bone and cartilage formation may be of particular interest for follow-up studies.
Olsen
H G
HG
Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, N-1432 As, Norway. hanne-gro.olsen@umb.no
Meuwissen
T H E
TH
Nilsen
H
H
Svendsen
M
M
Lien
S
S
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000235:genetics*; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics*; D004420:Dystocia / Q000235:genetics / Q000662:veterinary*; D005260:Female; D015810:Linkage Disequilibrium; D011247:Pregnancy; D040641:Quantitative Trait Loci / Q000235:genetics*